So if you putting heavy cream in your coffee makes the difference between fasting and not fasting, then go for it. But my personal opinion is that fasting should be committed to in full. If you don't like black coffee (heresy), then don't drink coffee. Just don't think about food. Drink water. Get stuff done. Drink tea. Or ignore me, whatever. I just like the idea of fasting and going without, and everyone searching for loopholes always chafes.